1. No category

Handling and Use of Glycerin
in Feed
Joe Harris, Ph.D.
Westway Feed Products, Inc.
Jan. 9, 2007
Objectives of Discussion
• Explain why feed manufacturers have interest in biodiesel derived glycerin
• Describe how glycerin impacts the physical
characteristics, nutritional properties and palatability of
feeds
• Describe the developmental process we have used in
evaluation of this material as a possible component of
our products in terms of:
– Approved supplier process/ Characterization of available
products/ Evaluation of possible contaminants
– Development of realistic specifications as an ingredient
– Development of Standard operating procedures for this material
– Internal evaluation of safety of various sources for use in feed
Why Glycerin?
100
100 95
100
80
81
80
56
60
40
Relative Energy Value
(Ruminant TDN as fed values as % of starch)
Starch
Sugar
Corn
Glycerin (100%)
Glycerin (80%)
Cane Molasses
Why Now?
Supplies of glycerin have grown dramatically with
increases in bio-diesel production. This has saturated
saturating historic uses. Until such time as additional
applications are developed-glycerin will compete with
traditional energy feeds on a price basis.
Business synergies exists between feed industry and
bio-diesel industries
Why Glycerin?
• Glycerin’s unique physical properties that make it
attractive as a component of liquid feed supplements:
– Highly water soluble.
– Melting point of 64 degrees F if absolutely pure but when small
amounts of water are present it remains fluid at temperatures
near zero.
– Mild pleasant aroma
– Sweet Taste
– Near Neutral ph- typical 5 to 7
– Highly palatable
– Decreases the viscosity of molasses and other liquid by-products
– Hydroscopic-attracts moisture-which can help prevent feeds
from “drying out” at low humidity.
Moisture Content of Crude Glycerin By Producer
25.00
20.00
%
15.00
10.00
13
12
19
47
11
3
4
4
5.00
0.00
A
B
C
D
E
Producer
Values shown in bars represent
number of samples analyzed
F
G
H
Primary Ash Constituents in Crude Glycerin from Different Producers
12.00
10.00
8.00
Potassium
%
Sodium
6.00
Sulfur
Chloride
Ash
4.00
2.00
0.00
A
B
C
D
E
Producer
F
G
H
Methanol Content in Crude Glycerin by Producer
4500
4
4000
3
3500
ppm
3000
2500
11
2000
19
11
4
47
1500
1000
500
0
11
A
B
C
D
E
Producer
Values shown in bars represent
number of samples analyzed
F
G
H
Glycerin Content in Crude Glycerin as a % of Organic Matter by Producer
100.00
99.00
98.00
97.00
%
96.00
95.00
94.00
93.00
13
12
19
45
11
3
4
92.00
4
91.00
90.00
A
B
C
D
E
Producer
Values shown in bars represent
number of samples analyzed
F
G
H
Highly Toxic Heavy Metals in Crude Glycerin
4
3.5
A
2.5
B
2
C
1.5
D
0.5
E
0.3
0.6
0.4
1
0.5
ppm
2
2
3
G
Max Tol. In
Complete Feeds
0
Cadmium
Mercury
Metal
Selenium
Toxic Heavy Metals in Crude Glycerin
35
30
30
A
25
20
B
20
C
15
D
10
E
ppm
G
5
Max Tol. In
Complete Feeds
0
Barium
Lead
Metal
Moderately Toxic Heavy Metals in Crude Glycerin
120
100
100
A
80
B
C
ppm 60
50
50
D
40
0
Arsenic
1.67
0.32
G
0.86
20
E
Nickel
Metal
Max Tol. In
Complete Feeds
Silver
Slightly Toxic Heavy Metals in Crude Glycerin
1200
1000
1000
A
800
B
C
ppm 600
D
400
E
G
200
0.26
0.58
0
Chromium
Metal
Max Tol. In
Complete Feeds
Impact of Glycerin on Physical Properties of
Textured
Feed Conditioner
Glycerin Viscosity Comparison
140
120
Control
Viscosity (cps)
100
5% Glycerin
4% Prop Glyco
MgCl Solution and Glycol
80
4% MgCl Solution
10% Glycerin
60
10% MgCl Solution
40
20
20
30
40
50
Temperature (F)
60
70
80
Evaluation of Liquid Supplements Added to Low
Quality Forage in Continuous Culture of Rumen
Microbes ’06 West Virginia University
•
Procedures
– A poor quality hay was selected for the study so as to compare
well to dormant season grazing pasture conditions. Hay
contained 6.3% crude protein and 72.6% Neutral Detergent
Fiber
– Comparisons Included Hay alone vs. Conventional Liquid
supplement –exclusively Molasses based (CLS), and
Conventional Liquid Supplement containing Molasses +
Glycerol (GLY)
– Liquid supplements were added at 10 % Dry Basis to the Hay in
treated cases in an in-vitro continuous culture system.
Evaluation of Liquid Supplements Added to
Low Quality Forage in Continuous Culture of
Rumen Microbes
Digestibility of Dietary Nutrients %
Results
100
– Dramatic impact on
digestibility of dietary fiber
(Neutral Detergent Fiber)
was observed –Increased by
80
a factor of nearly 8 times
– Digestibility of Non-Structural
Carbohydrates (NSC) was
60
high in all cases as expected
– Note TDN est = sum of
40
digestible NDF, NSC and CP
Hay
Alone
Hay +
CLS
Hay +
GLY
20
0
NDF
NSC
Crude
Protein
T DN
est
Impact on Measured Parameters
Evaluation of Liquid Supplements (Conventional and 40% Glycerol)
Added to Medium Quality Forage
TK Miller, RFPL- WVA10-06
•
140
120
100
•
–
–
80
CLS
Gly
60
–
–
40
•
20
0
Study was designed to compare
impact replacing molasses with
glycerin on dry basis in a
conventional liquid supplement.
Approximately 40% glycerin was
included in the LFS with 12.5%
molasses vs typical all molasses
based LFS.
Results
DMD %
Ammonia
mg/dl
Microbial N TVFA's mg/d
g/d*100
Dry matter digestibility not different
Ammonia content and yield of
microbial Nitrogen not different
Total production of Volatile Fatty
acids tended to be higher in glycerin
supplement with amount of acetic
acid lower and butyric acid higher
Ph data implies drop post feeding
was less with the glycerin based feed.
(next slide)
Conclusion- replacement of
molasses with glycerin should not
impact digestive performance of
liquid supplements.
Impact of Glycerin (40%) on rumen culture ph
6.7
6.675
6.65
pH
6.625
6.6
6.575
6.55
6.525
6.5
-5
0
5
10
15
Hours relative to feeding
CLS
GLY
20
25
TABLE 5. Effect of Liquid Supplement on Volatile Fatty Acid Production and pH
Treatments
Component
CLS
GLY
P=
Total VFA
181
178
0.73
Acetic
121
107
0.06
Propionic
41
42
0.22
Iso-butyric
0.46
0.55
0.06
Butyric
16
27
0.0008
Isovaleric
0
0
.
Valeric
2.4
2.4
0.93
Acetic
67.1
59.9
0.0011
Propionic
22.5
23.4
0.13
Iso-butyric
0.26
0.31
0.02
Butyric
8.8
15.0
Isovaleric
0.0
Valeric
1.3
mM/day :
Molar %
0.0009
0.0
1.4
.
0.79
CONSUMPTION STUDIES
Effect of adding USP glycerin to equine feed to determine if feed refusal is
an issue:
Added 1% glycerin to normal ration. Fed eight horses - 1 colt, 4 Thoroughbred
mares, 1 Arab mare, 1 Arab gelding, 1 Thoroughbred gelding. Ages range from 6
months to 29 yrs.
Everything was cleaned up in normal time. Each horse took the first bite, chewed
it up, and went back for the next with no hesitation. Bottom line is 1% glycerin
caused no noticeable difference to the horses.
Consumption of high crude glycerin biodiesel origin content liquid
supplement by pregnant beef cows confined in a dry lot: Two groups of beef
cows were separated into pens in a dry lot. Both groups were offered a liquid
supplement that contained 42.43% glycerin (formula shown below) and a diet
consisting of cotton seed burrs and a 30% burr ration. One group was fed with a
typical lick wheel feeder while the other group was fed using an open trough
feeder. The trial period for the consumption study was 18 days. Diet and
performance data are summarized below. As expected, the cattle consuming the
liquid supplement from the open trough consumed more than the cattle exposed to
the lick wheel feeder (10.6 vs. 7.0 lbs/hd/day). From this information it is
ascertainable that feed refusal due to glycerin is not an issue. Further more the
cows performed well on the product averaging 1.7 lbs/hd/day gain over the 18 day
period.
Methanol Considerations
•
•
•
•
•
Human metabolism includes conversion to formaldehyde and then formic acid-formic
acid responsible for toxic effects- in some species excretion via respiration and urine
is documented
CFR 573.460 permits use of formaldehyde in feeds wherein approximately 25 % of
animals diet is comprised of a protein meal treated with up to 1% formaldehyde. This
would equate to approximately 0.25% dietary formaldehyde. Molecular weight of
formaldehyde is 30.03 and molecular weight of methanol is 32. .25*(32.04/30.03) =
.2667 % Substituting methanol for formaldehyde and assuming 20% glycerin in diet
would equate to .2667/20 or 1.333 % methanol in glycerin source
CFR 573.480 describes use of formic acid in hay crop silages as a preservative not to
exceed 2.25% on dry weight basis- assuming 50% silage on a dry basis in diet would
provide 1.125% formic acid. Formic acid m.wt. = 46.02. Methanol m.wt. = 32.04.
Adjusting for molecular wt. 1.125 *(32/46) = .783% . .783/20 = would equate to
3.915% methanol in a glycerin source fed at 20% of diet to ruminant animals.
CFR 573.640 describes the use of “methyl-esters” of higher fatty acids for use in
animal feeds. Methyl-esters are considered non-toxic with LD 50 > 17.4 g/kg in rats.
Digestion includes the release of methanol from the fatty acid. As a portion of
molecular weight assuming C-16/0 as an average- methanol yield equals
approximately 11.83% of inclusion of the methyl-esters. If diets contained 5 % methyl
esters 5 X 0.1183= methanol contribution (.5915%). Again using a 20% inclusion of
glycerin source .5915/20 = 2.957% methanol concentration in glycerin would be
equivalent.
Numerous literature references are available relative to feeding formic acid or its’
calcium/potassium salts at levels near 1% on a formic acid basis. Methanol
concentrations in order to reach this level and again adjusted for relative molecular
weights would equal 1*(32/46) = 0.695 %. With glycerin content of 20% in diets
.695/20 = 3.478% methanol would need to be present to provide these levels.
Methanol Considerations cont.
•
EPA, 1994 cites a no observed adverse effect level (NOAEL) of 500mg/kg/day for rats fed 90
days.
– Assuming a dietary dry matter intake of 2.3 % of body weight (23 grams/kg) a value of
0.5g/23g= 2.17 % of total diet. If glycerin was source at 20% of diet 2.17/20 = 10.85%
methanol concentration tolerable in glycerin.
– NOAEL level can be extrapolated in number of ways. A factor for interspecies differences
could be applied and a factor for sensitive sub-populations could be applied. Assuming a
safety factor of 3 for possible species differences and a factor of 10 for possible sensitive
sub-populations an acceptable daily intake (ADI) would be calculated as 500/(3x10) = 17
mg/kg/d
ADI(m g/k g/d) =
Spe cie s
17
Age (w k s ) bw t (k g)
%Glyce rin in Die t =
FI (g/k g bw t) ppm M tOH (m ax)
Chick e ns , broile rs
2
0.3
160
1063
Chick e ns , broile rs
7
2.1
62
2742
Chick e ns laye rs
20
1.3
46
3696
Chick e ns laye rs
40
1.9
47
3617
4
62
2742
Sw ine m ature
100
31
5484
Cattle grow ing
135
27
6296
Cattle be e f m ature
500
20
8500
Cattle , dairy lactating
600
32
5313
Hors e s (conce ntrate )
500
12
14167
Sw ine young
10
S.O.P. Development Documentation
Proposed Quality / Usage Parameters (Glycerin-Feed Grade)
Chemical Properties:
Moisture
5-25%
Glycerol
> = 95% of the organic matter
Phosphorus
Potassium
0.3% max in dry matter
3% max in dry matter
Sodium
3.9% max in dry matter
Chloride
Guaranteed by supplier
Sulfur
Guaranteed by supplier
Methyl Esters
1% max in dry matter
Fat
1% max in dry matter
Methanol (Method AOAC
973.23 GCFID 16th ed. 1995)
Total Ash
0.75% max in dry matter
12% max in dry matter
Lead
30 ppm max in dry matter
Cadmium
0.5 ppm max in dry matter
Nickel
50 ppm max in dry matter
Mercury
2.0 ppm max in dry matter
Selenium
2.0 ppm in the dry matter
Arsenic
50 ppm max in dry matter
Proposed Quality/Usage Parameters (cont.)
Glycerin-Feed Grade
Physical Properties:
• Mild pleasant aroma
• Near neutral ph- 5 to
7.0
Usage Guidelines: via Labeling
•Not to be used in combination in diets containing formic
acid, formaldehyde and methyl-esters.
•Guarantees for moisture, ash, sodium, potassium,
sulfur and chloride maximums
•Limited inclusion rate in feeds i.e. poultry diets (5-10%),
equines and swine (10% ) and ruminants ( 20%)
Summary
• Glycerin from bio-diesel production is:
• An energy dense, palatable material for use in
feed
• Of high purity-particularly when evaluated on an
organic matter basis
• Low in concentrations of heavy metals
• Low in methanol concentration compared when
compared levels of either metabolites approved
for feed use or published toxicity values
• Can represent a value to animal feeding
programs